JMU Bio 140 Lab Final

The variable that is manipulated in an experiment is typically called the:
a) independent variable
b) dependent variable
c) control
d) causal variable

a

This is defined as a proposed explanation for an observation
a) experiment
b) conclusion
c) prediction
d) hypothesis

d

Type of study that tests a hypothesis but does not manipulate any variables
a) quantitative
b) non-experimental
c) experimental
d) descriptive

b

You want to test the hypothesis that marigolds repel salamanders. Which of the following studies DOES NOT test this hypothesis.
a) Find 30 flowerbeds of equal size that have different numbers of marigolds in them. Count the number of salamanders in each flowerbed and see if the number of salamanders in each bed is related to the number of marigolds in each bed
b) Find 30 flower beds on campus and compare the total number of salamanders in flowerbeds with marigolds vs. beds without marigolds
c) Find 20 identical flowerbeds with salamanders in each. Plant marigolds in 10 of the flowerbeds and keep the other 10 flowerbeds as controls. After a month count the number of salamanders remaining in each type of flowerbed
d) Observe how salamanders react/move when they are close to marigolds vs. other species of flowers in the flowerbed
e) Find 30 flower beds on campus and count the total number of salamanders in each flowerbed

e

A scientist wishes to determine the effect of a digestive enzyme on starch digestion (starch is broken down into glucose). The experimental setup is to mix the enzyme with starch in a test tube, stop the reaction after a known period of time, and then measure the amount of glucose produced.

Which of the following is the correct experimental control?
a) maintaining a constant temperature during the experiment
b) An identical setup but replacing the enzyme with an equal volume of the same enzyme AFTER it has been inactivated.
c) Repeating the experiment three more times to control for any variation in your first experimental trial
d) An identical setup but replacing the enzyme with a different digestive enzyme

d

You want to test the hypothesis that marigolds repel salamanders. You design several studies to test this hypothesis. Which of the following studies would demonstrate that marigolds CAUSE salamanders to move out of flowerbeds?

a) Observe how salamanders react/move when they are close to marigolds vs. other species of flowers in the flowerbed
b) Find 30 flower beds on campus and compare the total number of salamanders in flowerbeds with marigolds vs. beds without marigolds
c) Find 20 identical flowerbeds with salamanders in each. Plant marigolds in 10 of the flowerbeds and keep the other 10 flowerbeds as controls. After a month count the number of salamanders remaining in each type of flowerbed
d) Find 30 flowerbeds of equal size that have different numbers of marigolds in them. Count the number of salamanders in each flowerbed and see if the number of salamanders in each bed is related to the number of marigolds in each bed

c

Which of the following are correct statements about hypotheses (check each)?
a) hypotheses are the same as predictions/expectations
b) hypotheses have explanatory power
c) hypotheses are guesses
d) hypotheses are usually based on background knowledge and prior observations

b and d

why is it important to post-rinse when pipetting volumes less than 20 microliters?
a) Small volumes may not get expelled completely due to surface tension.
b) Small volumes will evaporate prior to transfer
c) You can't accurately pipette less than 20 microliters.
d) You don't need to post-rinse small volumes.

a

Pipettors are most accurate in the middle to top end of their volume range
a) true
b) false

a

how can contamination be prevented in the laboratory?
a) Using barrier pipette tips.
b) Any of these methods will help prevent contamination in the laboratory.
c) Changing pipette tips between solutions, or after tips have touched DNA.
d) Keeping test tubes and pipette tip boxes closed as much as possible.

b

45.3 µL (microliters) = ________ mL (milliliters)
a) 0.0453 mL
b) 4,530 mL
c) 0.00453 mL
d) 45,300 mL

a

Test tubes should always be placed into a centrifuge with the hinges facing inward (T/F)

False

The detergent and salt in DNA extraction buffer dissolve membranes and dissociate proteins from the DNA (T/F)

True

Which of the following is NOT a tip for successful pipetting?
a) Hold the pipettor horizontally after filling the pipet tip
b) Change the tip when pipetting a new solution
c) Apply a tip before using a pipettor
d) Pipet slowly and evenly to prevent bubbles
e) Set the pipettor within its range

a

what is the main purpose of PCR?
a) to magnify DNA
b) to sequence DNA
c) to amplify DNA
d) to extract DNA from cells

c

This is an enzyme whose function is to synthesize new DNA by attaching nucleotides that are complementary to a single strand of DNA.
a) Adenosine Triphosphate
b) DNA polymerase
c) Nucleotides
d) Primers

b

Which of the following is NOT a term that can be used for the DNA that you want to make copies of in a PCR?
a) Template DNA (or template)
b) Expansion DNA (or DNA expansion)
c) DNA extract (or extracted DNA)

b

Short, single stranded pieces of DNA that are designed to base pair (or match up with) a specific segment of DNA you want to copy are called:
a) DNA polymerase
b) primers
c) nucleotides
d) probes

b

The building blocks of DNA are:
a) primers
b) DNA polymerase
c) nucleotides
d) nucleic acids

c

Nucleotides are added to the growing DNA strand during the _________ phase
a) denaturation
b) annealing
c) preparation
d) extension

d

in sequential order, what are the three steps of PCR?
a) Anneal Primers, Extend DNA, Denature DNA
b) Denature DNA, Anneal Primers, Extend DNA
c) Extend DNA, Anneal Primers, Denature DNA
d) Denature DNA, Extend DNA, Anneal Primers

b

Click each of the following that is a necessary "ingredient" for a PCR to proceed

template dna
reverse primer
nucleotides
forward primer
dna polymerase

If no DNA polymerase (or Taq polymerase) were included in your PCR, the reaction would not work because:
a) The DNA could not split into single strands
b) There would be no building blocks for the DNA polymerase to use to make new strands of DNA
c) There is no enzyme to make new complementary strands of DNA

c

If no primers were included in your PCR the reaction would not work because
a) Complementary base pairing would not occur in any DNA strands
b) There would be no building blocks for the DNA polymerase to use to make new strands of DNA
c) The DNA polymerase would not amplify the specific region of DNA you want to be amplified
d) The DNA could not split into single strands

c

The three main stages of the PCR process are usually repeated around 30 times over several hours. Approximately how many copies of the target region of original DNA molecule are made during that time?
a)100 thousand
b) 1 billion
c) 1 million
d) 1 thousand

b

During PCR, DNA polymerase (or Taq polymerase) starts copying at
a) The end of free single stranded DNA
b) The start codon
c) Any open point
d) Primers attached to the end of the desired DNA sequence

d

electrophoresis is used to
a) Separate DNA fragments
b) Determine the size of DNA fragments
c) Determine the presence of DNA fragments of certain size
d) All of these

d

DNA possesses:
a) A net negative charge
b) A net positive charge
c) No net charge

a

The rate at which DNA migrates through the gel is determined by:
a) molecular size of DNA
b) the length of the agarose gel
c) the amount of loading dye added
d) the number of wells in the gel

a

Why do we dye our gels with Ethidium bromide or Gel Red dyes?
a) These dyes stain the double stranded DNA in our gel
b) These dyes will stain the proteins in our gel
c) These dyes will only stain the single stranded RNAs in our gel

a

Why do scientists load DNA of known sizes (also called "marker" or "ladder") into the agarose gel?
a) It makes it easier to determine sizes of unknowns using comparison techniques
b) To fill in all the slots on the gel so you can run it
c) To practice loading the DNA before you get to the important DNA.
d) So you know how long the gel needs to run

a

Which of the following provides clues that your gel electrophoresis is running properly (check all that apply)
a) bubbles rise from the electrodes
b) you can see the loading dye move from the well into the gel
c) you can see the DNA moving in the gel

a and b

Which of the following statements about gel electrophoresis is correct?
a) Longer DNA fragments migrate farther than shorter fragments
b) Migration distance is inversely proportional to the fragment size
c) Positively charged DNA migrates more rapidly than negatively charged DNA
d) None of these statements are true

b

The rate of migration of DNA within an agarose gel in the gel electrophoresis technique is primarily based on what factor?
a) The size of the DNA fragments
b) The number of DNA fragments
c) The size of the wells of the gel
d) The volume of the DNA sample loaded

a

When two bands match up between two different samples on a gel, this means
a) The samples share a fragment of DNA that is the same length
b) Nothing
c) The two samples are unrelated
d) The PCR didn't work

a

Why do we run our H2O control (aka negative control) from our PCR reactions on the gel?
a) It enables you to tell if your PCR was contaminated by DNA that was not from your sample
b) It enables you to tell whether or not you included primers in your PCR
c) It enables you to tell whether or not the polymerase was functioning properly in your PCR

a)

To carry out Sanger sequencing, a mix is needed containing
a) DNA polymerase
b) Primer
c) DNA template
d) four deoxyribonucleotides (A, T, C, G)
e) dideoxyribonucleotides (ddNTPs)

all of the above

The primer used in Sanger sequencing
a) Can have any nucleotide sequence
b) Has a nucleotide sequence complementary to the areas that flank (or surround) the region you want to sequence
c) No primer is required for Sanger sequencing
d) Must have a sequence beginning and ending with the same nucleotide

b

A laboratory might use ddNTPs (dideoxyribonucleotides) to _____.
a) sequence a DNA fragment
b) Separate DNA fragments
c) visualize DNA expression
d) clone the breakpoints of cut DNA

a

The dideoxyribonucleotides (ddNTPs) used in DNA sequencing work to ______.
a) stop the growth of a DNA strand at a particular base (A, T, G, or C)
b) reduce the error rate of the sequencing reaction
c) allow the specialized DNA polymerase used in sequencing to extend the DNA strand
d) allow the DNA synthesis reaction to proceed at higher temperatures and therefore run faster

a

Since dideoxy (Sanger) sequencing is based on chain termination, why are normal dNTPs (deoxyribonucleotides like A, T, G, and C) also included in the reaction?
a) to provide a substrate for RNA polymerase
b) to produce a range of sizes of DNA synthesis products that terminate at a variety of lengths
c) to enhance the chain termination ability of the dideoxynucleotides

b

In the last steps of Sanger sequencing, the DNAs produced in a DNA sequencing reaction are analyzed on the basis of their ______.
a) positive charge
b) shape
c) length of time needed for cloning
d) size or length

d

The final step in a Sanger DNA sequencing reaction is to run the DNA fragments on a gel. What purpose does this serve?
a) It separates DNA fragments generated during the sequencing reaction based on one-nucleotide differences in their size.
b) It adds ddNTP to the end of each DNA fragment.
c) It separates DNA fragments based on their charge.
d) It changes the length of the DNA fragments.

a

which of the following are good times to use a diagram
a) when conveying background information to an audience
b) when showing experimental strategies and techniques
c) when proposing a model
d) all of these are good times to use a diagram

d

The most important consideration for designing a good diagram is:
a) To clearly define the purpose of the diagram
b) to clearly define your color scheme
c) to choose a wise text font
d) to label items properly

a

Which of the following poster sections is optional?
a) results
b) summary/conclusion
c) hypothesis/question/goal
d) title
e) methods
f) background/introduction

e

What type of correlation is there between the amount of text on a poster and the likelihood that someone will read it?
a) direct
b) inverse
c) none

b

number of unique species found in an area

species richness

Shannon Diversity

measure of biodiversity that accounts for species richness and evenness

biodiversity

increases as more tips and branches are added to the tree of life

ecosystem services

direct and indirect benefits that humans derive from other organisms

habitat destruction

one of the worst threats to biodiversity

What is the main goal of our biodiversity study this week?

to compare biodiversity at a forest edge vs forest interior